Electrical connectors for electrically interconnecting two surfaces have been known as least as early as July, 1970 as exemplified in U.S. Pat. No. 3,638,163 to Loosme. Patentee Loosme disclosed therein a cylindrical, non-conductive body having a plurality of spaced apart conductive contacts wrapped therearound for being placed between parallel surfaces having conductive strips thereon. The strips then were electrically interconnected through the contacts.
Subsequent to Loosme, Y. Kotaka disclosed in U.S. Pat. No. 3,795,884 a connector comprising an insulating block having coil springs encapsulated therein. Each coil, electrically isolated from adjacent coils by an axial cut in one surface of the block, extended outwardly from diametric surfaces of the block to engage conductors on parallel printed circuit boards.
Thereafter, on Oct. 12, 1976, W. R. Evans issued U.S. Pat. No. 3,985,413 disclosing a connector comprising a generally cylindrical elastomeric body having a thin non-yielding flexible circuit wrapped therearound. Upon placing the connector between two parallel substrates and being compressed, corresponding conductors on the substrates will be electrically connected by the conductors on the flexible circuit.
In 1987, a P. J. Balsells issued U.S. Pat. No. 4,655,462 disclosing a coil spring with each coil being disposed at a preselected acute angle with the centerline of the spring. This type of spring, referred to as a "canted" coil spring, exerts a constant force in a loading direction normal to the centerline over a substantial range of deflection. Capitalizing on this feature, one of the co-inventors of the present invention, proposed the use of canted coil springs as biasing members in a card edge connector. It is now proposed to use canted coil springs as electrical connectors for electrically interconnecting two parallel surfaces.